1. Field of the Invention
The present invention relates to a management system and management method for managing communication apparatuses, and more particularly, to a management system and management method for managing multiple Voice over Internet Protocol (VoIP) terminals in an IP telephony system.
2. Description of the Related Art
In the IP telephony system, a Multimedia Gateway Controller (MGC) controls multiple VoIP terminals via an IP network. Examples of the IP network include the Internet, an intranet, and a local area network (LAN). Examples of the VoIP terminals include a media gateway, a media converter, and an IP telephone.
Conventionally, in the IP telephony system, a periodic health check is performed by the MGC, as a means of normality diagnosis of a VoIP terminal. The cycle of performing the health check is uniquely determined independently of the VoIP terminal in the IP telephony system. The MGC issues a diagnosis request to a VoIP terminal at regular intervals and diagnoses the status of the VoIP terminal after waiting for the response from the VoIP terminal.
When the MGC judges that the VoIP terminal is abnormal through the response from the VoIP terminal, the MGC issues a reset instruction as a remedy to the VoIP terminal. Upon reception of the reset instruction, the VoIP terminal immediately performs a reset processing. The VoIP terminal then performs registration processing with respect to the MGC to work again. With this operation, the VoIP terminal works for a recovery from the abnormal status.
However, with this method, when the MGC performs the health check with respect to multiple VoIP terminals and judges that the multiple VoIP terminals become abnormal at the same time due to en excessively high load imposed on the network, the MGC issues a reset instruction to the multiple VoIP terminals at the approximately same time. Accordingly, the multiple VoIP terminals try to perform the reset processing and the registration processing simultaneously. As a result, the following problems may occur.
First, a further increase of network traffic may be caused by transmitting and receiving registration messages between the MGC and the multiple VoIP terminals. Furthermore, an excessively high load may also be imposed on the MGC.
Second, since the function of the VoIP terminal is unable to be used until the VoIP terminal completes the reset processing and the registration processing, the multiple VoIP terminals may be unable to be used at the same time. As a result, when a redundant system or a communication hierarchy is configured by the multiple VoIP terminals, there is also possibility that the advantage cannot be used enough.
A method to prevent a network traffic increase by changing the interval of the health check include a measure disclosed in Japanese Patent Laid-Open No. 10-327148, for example. In this method, an interval at which a management apparatus performs polling with respect to a management target apparatus is dynamically changed depending on a traffic state of a network. It should be noted that the “polling” means that the management apparatus sends to a management target apparatus a diagnosis request to diagnose the status of the management target apparatus at constant intervals, and the management target apparatus returns a response to the diagnosis request.
However, even this method has the same problems as described above in the case where the management apparatus manages multiple management target apparatuses. This method needs to dynamically change the polling interval for each of the multiple management target apparatuses, in the case of performing the polling with a different timing among the multiple management target apparatuses. Thus, the management apparatus is required to perform a very complicated operation. Furthermore, this method has another problem in that the management of the multiple management target apparatuses is excessively concentrated on the management apparatus.